The present invention relates to a method and apparatus for thermal processing of biomass.
Nothing in the following discussion of the state of the art is to be construed as an admission of prior art.
To ensure clarity, it is necessary to establish the definition of several important terms and expressions that will be used throughout this disclosure.
The term “biomass” is used here in a generic sense and may refer to a mixture of relatively dry “biological residue” and a relatively dry catalytically active bio-substance (“biocatalyst”). Biological residue as well as biocatalyst, alone or together, should have a moisture content of not more than 2-5%. Both substances may predominantly involve waste products obtained in large amounts in agriculture. Thus, the present invention is also directed to the disposal of biological waste while producing an energy carrier (fuel).
The term “biological residue” involves primarily wood residues (e.g. sawdust), leaves, rapeseed cake, sugar beet residues, husks obtained during beer brewing or liquor production, solids from olive oil production, animal meal, cellulose from paper production, press cake from feedstock production for animals, straw from wheat, barley or other crop, or other bio-substances, such as various grains, corn, etc.
The term “biocatalyst” involves predominantly bio-substances which take up a certain amount of catalytically active elements, minerals or other compositions present in the ground, as they grow. It has been shown that, e.g., a certain content of inorganic substances have a catalytic effect on biological residues. These types of bio-substances with mineral constituents involve, e.g., rapeseed roots, rapeseed straw, or sugar beet residues (pressed sugar beets).
The method according to the present invention is applicable for example to a mixture of sugar beet residues (presumably biological residue), on one hand, and sugar beet residues (presumably biocatalyst), on the other hand, or to a mixture of rapeseed cake (presumably biological residue) on one hand, and rapeseed straw (presumably biocatalyst), on the other hand.
It would be desirable and advantageous to provide an improved method and apparatus for processing biomass to obviate prior art shortcomings.